Johnny Damon knows Jacoby Ellsbury and knows all about being a centerfielder who leaves the Red Sox to sign with the Yankees.

Damon did it before the 2006 season, signing a four-year, $52-million deal to join the Yankees. That contract looks paltry now compared with the seven-year, $153-million deal Ellsbury and the Yankees have agreed to, according to a source.

Damon won a World Series with the Red Sox in 2004 and the Yankees in 2009. He thinks adding Ellsbury -- a World Series champion with Boston in 2007 and this past season -- will help the Yankees mightily in their quest for another title.

"I think it's a great signing for the Yankees and a great signing for Jacoby," Damon said Wednesday morning in a telephone interview. "He's a real game-changer. He's had some injuries and that could be an issue, but there's no doubt he's going to help New York."

What about moving from Boston to the Bronx?

Damon, once a beloved, scraggily haired member of the 2004 "Idiots," was vilified whenever he returned to Fenway Park as a Yankee.

"I think he'll hear some cheers and some boos," Damon said of Ellsbury. "Some people are going to forget what he did there, but he'll be able to handle it. Maybe the Red Sox could have come up [in their contract offer] if they wanted him to stay. Jacoby did better than me in Boston -- he won two World Series and I only won one."

Damon marveled at the money Ellsbury was able to get. It's the third-biggest deal for an outfielder in MLB history, behind the eight-year, $160-million deals received by Manny Ramirez (Boston) and Matt Kemp (Dodgers).

"Sets a new level for centerfielders," Damon said. "Kenny Lofton set a new level for me and then I set a new level for Jacoby. It's great for centerfielders and it's great for baseball."